Oxidative process for the removal of carbon monoxide from non-catalytic oxidative dehydrogenation product streams

ABSTRACT

A method of removing CO from a mixture of CO and saturated and unsaturated hydrocarbons CO to CO 2  is provided. In one embodiment, the method is to contact feed stream with an oxygen transfer agent; and then oxidize at least a portion of the CO to CO 2  to produce a stream enriched in CO 2 . The saturated and unsaturated hydrocarbons in the feed are not further oxidized during the oxidation. The oxygen transfer agent includes at least one of: i) water; ii) at least one reducible metal oxide; iii) at least one reducible chalcogen; or mixtures thereof. In another embodiment, the CO is converted to methane. The unsaturated hydrocarbons in the feed are not hydrogenated. In both of these alternatives, the CO 2  or methane are then removed. Systems for removing the CO are also provided.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority from U.S.Provisional Application No. 63/224,880, filed on Jul. 23, 2021, thedisclosure of which is incorporated by reference herein in its entiretyfor all purposes.

TECHNICAL FIELD

The present disclosure is related to systems and methods for theefficient removal of by-product carbon monoxide from oxidativedehydrogenation processes.

BACKGROUND

Ethylene and propylene are important building blocks for thepetrochemical industry. These olefins are used in the manufacturing ofpolymers such as polyethylene, polypropylene, polystyrene and many morechemicals of commercial interest. Over 90% of the global olefinproduction comes from the high temperature steam cracking of naphtha orethane and propane. The steam cracking process, which utilizes furnaces,is highly energy intensive, and 1.5 to 2 tons of carbon dioxide isproduced for every ton of olefin product produced.

Natural gas production from shale deposits has dramatically increasedsupply of methane, ethane and propane in recent years. As a result ofthe continued global demand for olefins and the potential for a newgrowing supply of ethane and propane available in natural gas liquidsfrom shale deposits, a significant amount of interest and investment iscurrently centered around expanding the production capacity of ethyleneand propylene derived from these new sources. Numerous olefin grass rootand expansion projects are either under contract or in the planningstages to take advantage of the relative low cost liquids from wet shalegas. The supply of natural gas in the US has increased dramatically inrecent years as has the co-production of shale oil. Natural gas is oftenproduced as a mixture of methane and hydrocarbons such as ethane,propane and butanes. This so called “wet gas” often contains greaterthan 20% by volume of heavier components. To feed conventional ethanesteam cracking furnaces, capital and energy intensive equipment is usedto separate these gas components so that primarily ethane, orethane/propane, mixtures are fed to the steam crackers. However, thereare many environmental and cost challenges to bringing on this level ofnew capacity of steam crackers.

Olefin production is the largest emitter of CO₂ and NOx in the organicchemical industry. With worldwide per year of CO₂ and roughly 1.4MT/year of NOx. Projects located in severe EPA non-attainment zones arechallenged by the increase cost of NOx control. The total greenhouse gas(GHG) emission profile, reported in CO₂ equivalents, is another criticalpart of the permitting for all production expansions.

The industry continues to push for production technology that: (1)generates higher overall yield of ethylene and propylene; (2) increasesthe run length between furnace turnarounds (e.g. inspections, repairs,improvements, etc.); (3) lowers steam and energy utilization; (4) lowersall GHGs including carbon dioxide and NOx.

Oxidative dehydrogenation (ODH) of ethane and propane offers a potentialsolution for these needs provides an opportunity to improve theefficiency of olefin production. The oxidative coupling of methane (OCM)likewise offers an opportunity for such improvements. However, mostcurrent ODH and OCM processes produce carbon dioxide and carbon monoxideby-products at significantly higher levels than in the currentlypracticed steam cracking of ethane process. Therefore, there is a needfor improved systems and methods that that can efficiently separatethese unwanted by-products from the desired olefin products.

SUMMARY OF THE INVENTION

The inventors have discovered that carbon monoxide may be removed fromthe product stream produced by ODH and OCM of mixed hydrocarbon streamsby oxidation with water as an oxidation agent or with a selective oxygentransfer agent (OTA) to form CO₂. The CO₂ may then be more convenientlyremoved from the product stream. Importantly, both of these oxidationstrategies are performed at reaction conditions that do not furtheroxidize the product stream. This offers the benefit of minimal or noproduction of undesirable oxidation products such as alcohols andaldehydes, for example. According to certain embodiments, the inventivemethod and system offer improved process efficiency by using the sameoxygen transfer agent to both effect the ODH and/or the OCM and tooxidize the CO to CO₂, by merely changing the reaction conditions foreach step. This may be done by cycling the reaction conditions in asingle reactor, or by feeding the product stream from the ODH and/or OCMstep including the OTA to a subsequent reactor. Alternatively, or inaddition, the water that is produced as a side product of the ODH/OCMstep may be used to carry out the oxidation of the CO to CO₂.

The oxidation of carbon monoxide to carbon dioxide with concomitantproduction of hydrogen using water as the oxidant is also known as theWater Gas Shift (WGS) reaction. For the ODH process, it is important totransform the carbon oxide products to essentially all carbon dioxide sothat conventional carbon dioxide removal technologies, such the Benfieldprocess or amine extraction, may be employed to adequately remove allcarbon oxides from the olefin product stream.

In one embodiment, carbon monoxide (CO) is removed by the reaction witha selective oxygen transfer agent (OTA). In this process, CO is oxidizedto CO₂ by the stoichiometric reduction of the OTA, equation 1.

CO+OTA^(oxidized)→CO₂+OTA^(reduced)  (1)

OTA^(reduced)+02+OTA^(oxidized)  (2)

In a separate step, the reduced OTA may be re-oxidized (regenerated)with an oxygen containing gas, such as air.

In another embodiment, a process for the oxidative removal of CO fromODH product streams utilizes water as the oxidant. This process issimilar to the well-known Water Gas Shift (WGS) process and may beperformed either with, or without a catalyst.

A method of converting CO to CO₂ is provided. The method comprises,consists of or consists essentially of the following steps.

a) Contacting a first process stream comprising the CO and at least oneof C1 to C12 saturated and unsaturated hydrocarbons with an oxygentransfer agent.

b) Oxidizing at least a portion of the CO to CO₂ and reducing at least aportion of the oxygen transfer agent to a reduced oxygen transfer agent,at reaction conditions, to provide a second process stream comprisingthe CO₂, the reduced oxygen transfer agent, and the at least one of C1to C12 saturated and unsaturated hydrocarbons. In step b), the C1 to C12saturated and unsaturated hydrocarbons are not further oxidized.

The oxygen transfer agent comprises, consists of or consists essentiallyof at least one of the following:

i) water; ii) at least one reducible metal oxide; iii) at least onereducible chalcogen; mixtures of any combination of two or more of i),ii), and iii).

A system for oxidatively converting CO to CO₂ is also provided. Thesystem comprises, consists of, or consists essentially of:

at least one reactor configured for:

a) contacting a first process stream comprising the CO and at least oneof C1 to C12 saturated and unsaturated hydrocarbons with an oxygentransfer agent; and

b) oxidizing at least a portion of the CO to CO₂, at reactionconditions, and reducing at least a portion of the oxygen transfer agentto provide a second process stream comprising the CO₂, the reducedoxygen transfer agent, and the at least one of C1 to C12 saturated andunsaturated hydrocarbons; wherein the at least one of C1 to C12saturated and unsaturated hydrocarbons are not further oxidized.

The oxygen transfer agent comprises, consists of or consists essentiallyof at least one of:

i) water; ii) at least one reducible metal oxide; iii) at least onereducible chalcogen; any combination of two or more of i), ii), andiii).

A method of converting CO to CH₄ is provided. The method comprises,consists of or consists essentially of:

-   -   a) contacting a first process stream comprising the CO and at        least one C1 to C12 saturated and unsaturated hydrocarbons with        a hydrogenation catalyst and a source of H₂; and    -   b) reacting at least a portion of the CO with the H₂, at        reaction conditions, to provide a second process stream        comprising the CH₄ and water.

The first process stream comprising the CO is a hydrocarbon productstream resulting from the oxidative coupling of methane or oxidativedehydrogenation of hydrocarbons.

According to another embodiment, a method of converting CO to CH₄ isprovided. The method comprises, consists of or consists essentially ofthe following steps.

a) contacting a first process stream comprising the CO and at least oneC1 to C12 saturated and unsaturated hydrocarbons with a hydrogenationcatalyst and a source of H₂; and

b) reacting at least a portion of the CO with the H₂, at reactionconditions, to provide a second process stream comprising the CH₄ andwater.

The at least one of C1 to C12 unsaturated hydrocarbons are not reducedin step b); and the first process stream comprising the CO is ahydrocarbon product stream resulting from the oxidative coupling ofmethane or oxidative dehydrogenation of hydrocarbons.

According to an embodiment, a system for converting CO to CH₄ isprovided. The system comprises, consists of, or consists essentially of:

at least one reactor configured for:

a) contacting a first process stream comprising the CO and at least oneC1 to C12 saturated and unsaturated hydrocarbons with a hydrogenationcatalyst and a source of H₂; and

b) reacting at least a portion of the CO with the H₂, at reactionconditions, to provide a second process stream comprising the CH₄ andwater.

The at least one of C1 to C12 unsaturated hydrocarbons are not reducedin step b); and the first process stream comprising the CO is ahydrocarbon product stream resulting from the oxidative coupling ofmethane or oxidative dehydrogenation of hydrocarbons.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an exemplary system according to an embodiment of theinvention whereby CO is oxidized to CO₂ before employing techniques toremove CO₂;

FIG. 2 shows an embodiment of an exemplary system according to anembodiment of the invention whereby the byproduct CO is oxidized by anOTA and removed as CO₂ according to the invention;

FIG. 3 shows an embodiment of an exemplary system according to anembodiment of the invention whereby the byproduct CO is oxidized bywater via the WGS reaction and removed as CO₂ according to theinvention; and

FIG. 4 shows another exemplary system according to an embodiment of theinvention whereby CO is hydrogenated to methane for separation.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

The oxidative couple of methane (OCM) and the oxidative dehydrogenation(ODH) of ethane and propane to olefins offer production routes that cansignificantly reduce CO₂ emissions and virtually eliminate NOx emissionsfrom world scale plants. ODH is a selective process that producesprimarily ethylene and water as products, and is an exothermic reaction,shown below as reaction 1.

CH₃CH₃+½O₂→CH₂CH₂+H₂OΔH°=−105 kJ/mol  (1)

The oxidative coupling of methane (OCM) reaction to produce water islikewise exothermic, shown below as reaction 2.

CH₄+½O₂→CH₂CH₂+H₂OΔH°=−175 kJ/mol  (2)

The per-pass yields of the ODH reaction and the OCM reaction are notlimited by thermodynamic equilibrium, as it is in pyrolysis. Thepyrolysis of ethane is shown below as reaction 3.

CH₃CH₃+Heat⇄CH₂CH₂+H₂ΔH°=+137 kJ/mol  (3)

The oxidative coupling of methane (OCM) and the ODH of ethane and higherhydrocarbons such a propane are therefore reactions of significantcommercial value. The oxidative dehydrogenation of propane, likewise isan exothermic reaction and therefore is best performed in fluid bedreactors.

These conversions, either ODH of ethane or higher hydrocarbons or OCMmay be done either catalytically by feeding a hydrocarbon and an oxygencontaining gas, or in a redox oxygen transfer mode whereby an OxygenTransfer Agent (OTA) supplies the necessary oxygen for the formation ofwater and the reaction proceeds without oxygen. Either system isexemplified by equation (4):

zCnH_(2n+2−2β)+(z−1+δ)“O”→C_((z×n))H_(2(z×n)+2−2β−2δ)+(z−1+δ)H₂O  (4).

where z=the number of reacting molecules; n=the number of atomic unitsin the reacting molecule; β=the degree of unsaturation where the valueis zero for single bonds, one for double bonds and molecular rings, andtwo for triple bonds; and 6=the change in the degree of unsaturation.The oxygen, “O” in (4) may be supplied by the reduction of a metal oxideor via the catalytic use of molecular oxygen. The present inventors havefound that a single OTA may be used to effect any of the reactionsexemplified by reaction (4), but that differing reaction conditions areneeded for each hydrocarbon (methane, ethane, propane butanes, etc.) inthe feed. Either reaction (OCM or ODH) is exemplified by equation (4),and will be referred to herein as either OCM or ODH; i.e. for thepurposes of this disclosure, the terms, “oxidative coupling of methane”(OCM) and “oxidative dehydrogenation” (ODH) are considered to beinterchangeable.

One of the beneficial aspects of OCM and ODH as replacement technologiesfor conventional steam cracking is that the relative yields to theimportant olefin and aromatic products are very similar. Therefore,similar product recovery technologies may be employed for the removaland sale of the products. The major difference in the oxidativeproduction of olefins compared to their production via steam cracking isin the formation of higher levels of carbon oxide byproducts. Typicalyield comparisons between ethane steam pyrolysis and ethane ODH areshown in Table 1.

TABLE 1 Comparison of steam cracking and ODH yield, wt % Steam Cracking*ODH* Ethane 23.35% 6.02% Methane 2.35% 4.68% Acetylene 0.31% 0.10%Ethylene 34.88% 40.97% Propylene 0.75% 2.93% Propane 0.08% 0.31%Butadiene 1.20% 1.70% Butenes 0.13% 1.77% Butanes 0.14% 0.06% C5's 0.00%0.61% Benzene 0.31% 3.26% Toluene 0.05% 0.11% CO 0.03% 2.34% CO₂ 0.01%3.68% Coke 0.39% 0.00% Hydrogen 2.70% 0.85% Water 33.33% 30.61% Total100.00% 100.00% *From H. Zimmermann and R. Walzl, Linde, “Eullman'sEncyclopedia of Industrial Chemistry”, Wiley, 2012, p. 477. **From U.S.Pat. Nos. 10,138,182 B2; 10,968,149 B2; and 10,919,027 B1, all of whichare incorporated by reference herein in their entireties for allpurposes.

As shown in Table 1, ODH gives higher yields of ethylene, and othervaluable olefin and aromatic products compared to steam cracking.However, the less desirable products of carbon dioxide and carbonmonoxide are also higher for ODH. As shown in FIG. 1 , carbon dioxideand carbon monoxide should be removed before the cryogenic removal ofmethane and further purification of the olefins. Typical processes forthe removal of carbon dioxide from hydrocarbon streams, such as theBenfield process or amine extraction, are suitable for CO₂ removal butwill not function to remove the levels of carbon monoxide in the rangesproduced by the typical ODH processes. As shown in FIG. 4 , in anembodiment, methanation of the carbon monoxide may also be used toreduce the CO level. As shown in FIG. 2 , the methanation of CO to CH₄uses hydrogen.

Methods for Oxidative Conversion of Carbon Monoxide in a MixedHydrocarbon Product Stream to a Product Stream with the SelectiveConversion of Carbon Dioxide to Carbon Monoxide

FIG. 1 shows an embodiment of the methods and systems for converting COto CO₂ according to certain aspects of the invention. As shown in thefigure, ethane and air are fed to an ODH reactor. The feed to the ODHreactor may also include other saturated hydrocarbons, such as methaneand/or at least one of C3 to C12 hydrocarbons. The air provides oxygen.As discussed below, the oxygen is optional. In the ODH reactor, thehydrocarbons are oxidatively dehydrogenated at oxidative dehydrogenationreaction conditions to produce a process stream that includes saturatedand unsaturated hydrocarbons, water and a reduced oxygen transfer agent,as well as CO. The CO may be oxidatively converted to CO₂ using anoxygen transfer agent as described herein. According to certainembodiments, described in more detail below, at least a portion of theCO is oxidized to CO₂ and at least a portion of the oxygen transferagent is reduced to a reduced oxygen transfer agent, at reactionconditions, to provide the second process stream comprising the CO₂, thereduced oxygen transfer agent, and the at least one of C1 to C12saturated and unsaturated hydrocarbons which emerge from the COoxidation step as shown in FIG. 1 . Importantly, the C1 to C12 saturatedand unsaturated hydrocarbons are not further oxidized in the COoxidation step. The oxygen transfer agent comprises at least one of: i)water; ii) at least one reducible metal oxide; iii) at least onereducible chalcogen; or mixtures of any combination of two or more ofi), ii), and iii). The resulting CO₂ may be removed according to methodsas are known in the art. The process stream emerging from the CO₂removal step may be subjected to a step of demethanization. According tosome embodiments of the invention, the demethanizer may be place priorto the step where the CO is converted to CO₂. The demethanization maydone by pressure swing absorption, flashing, or distillation, forexample. Ethylene as a product is then taken off. Finally, the C3 andhigher products are taken off and the remaining ethane (and/or othermixed hydrocarbons) is recycled back to the ODH reactor.

FIG. 2 shows another embodiment of the invention. In FIG. 2 , the streamlabeled ODH effluent is the product of oxidative coupling of methane oroxidative dehydrogenation of hydrocarbons at hydrocarbon oxidationreaction conditions to produce a process stream that includes at leastone of CO and C1 to C12 saturated and unsaturated hydrocarbons. Thisstream is then sent to the REDOX CO oxidation reactor. In this reactor,the CO is oxidized to CO₂, using an oxygen transfer agent. The oxygentransfer agent is therefore reduced. Importantly, the reactionconditions in this reactor are such that the C1 to C12 saturated andunsaturated hydrocarbons are not further oxidized to undesirable acids,alcohols, or aldehydes. According to various embodiments of theinvention, the oxygen transfer agent may be the same as that used tooxidatively produce the ODH effluent that is fed to the CO oxidationstep. The REDOX CO oxidation reactor produces a stream that now isenriched in CO₂ and is sent to be further processed to remove CO₂ andwater. The effluent from this operation may be refrigerated and sent tothe demethanizer, which may be, for example, a pressure swing absorberunit. According to some embodiments of the invention, the demethanizermay be placed prior to the step where the CO is converted to CO₂.Hydrogen and fuel gas are taken off from the demethanizer and theremaining stream is sent to the de-ethanizer, where the C3 and higherhydrocarbons are taken off and sent to the C2 splitter where the desiredethylene product is taken off. The remaining ethane and other mixedhydrocarbons are recycled to the ODH reactor.

FIG. 3 shows an embodiment of the invention where water is used as theoxidant to convert the CO in the ODH effluent stream to CO₂, in ananalogous reaction to the water gas shift reaction. As shown in FIG. 3 ,ethane is depicted as a model compound in the feed stream 10 that is fedto the ODH and water gas reactor. It should be understood that thestream 10 could also include other hydrocarbons. As shown in FIG. 3 ,the ODH and water gas shift are shown as a single reactor. However,according to another embodiment, two reactors could also be used, suchthat the ODH is carried out in a first reactor and then the effluentfrom that ODH reactor, comprising mixed saturated and unsaturatedhydrocarbons, would then be fed to a water gas shift reactor. Asdiscussed above, the conditions in the ODH/water gas shift reactor aresuch that the hydrocarbons are not further oxidised to form undesirablealcohols, acids or aldehydes. Stream 30, which is now enriched in CO₂and also contains the products of the ODH reaction is fed to adownstream system to remove the CO₂ and to purify the desired ethyleneproduct. The removal of the CO₂ and the purification of ethylene may bedone according to methods as are known and used in the art. For example,the demethanizer could be placed prior to the CO₂ removal. As shown inFIG. 3 , in the compression, CO₂ removal and acetylene conversion stepproduces streams 35 (water) and 36 (CO₂). The product of thecompression, CO₂ removal and acetylene conversion step (sans water andCO₂) is refrigerated and that cold stream 40 is passed to thedemethanizer. In the example shown in FIG. 3 , the demethanization isdone via pressure swing absorption. The demethanized stream 50 is passedto the de-ethanizer, where the C3 and higher hydrocarbons are removed asstream 55. This may be done via a distillation process, for example.Stream 55 may be a product stream used as fuel or could be recycled backto the ODH reactor. Stream 60, which includes ethane and ethylene issent to the C2 splitter where the product ethylene stream 70 isproduced. The separated the ethane from the C2 splitter 75 is recycledback to the ODH reaction.

FIG. 4 shows another embodiment of the invention. In this embodiment,the CO in the product stream from the ODH reactor (ODH Effluent) isconverted to methane by reaction with hydrogen in a methanation process,rather than being oxidized to CO₂ as shown in FIG. 2 . Importantly, thereaction conditions in the methanation reactor are selected such thatthe unsaturated hydrocarbons in the feed are not hydrogenated. Accordingto various embodiments, a hydrogenation catalyst is generally used tocarry out the methanation. Methanation can be conducted in multiplestages. The first stage may use an iron oxide with chromium catalyst athigh temperature (300-560° C.) which gets CO concentrations down to2-3%. The second stage may use Cu/Zn oxide with alumina, at 200-260° C.Although a single reactor is shown in FIG. 3 , two or more reactors maybe employed if needed. The adiabatic temperature rise for methanation ofthis stream may be quite high—about 450° C. for this case. This isbecause of the relatively high CO concentration and the fact thathydrogen, which makes up over half of the feed on a molar basis, has alow heat capacity. Therefore, the reactor may be a packed shell-and-tubetype vertical reactor, generating high pressure steam on the shell side.

A method to convert CO to CO₂ is provided. The method comprises:

a) contacting a first process stream comprising the CO and at least oneof C1 to C12 saturated and unsaturated hydrocarbons with an oxygentransfer agent; and

b) oxidizing at least a portion of the CO to CO₂ and reducing at least aportion of the oxygen transfer agent to a reduced oxygen transfer agent,at reaction conditions, to provide a second process stream comprisingthe CO₂, the reduced oxygen transfer agent, and the at least one of C1to C12 saturated and unsaturated hydrocarbons; such that the C1 to C12saturated and unsaturated hydrocarbons are not further oxidized. Theoxygen transfer agent for the oxidation of the CO to the CO₂ comprisesat least one of: i) water; ii) at least one reducible metal oxide; iii)at least one reducible chalcogen; mixtures of any combination of two ormore of i), ii), and iii).

According to an embodiment of the invention, the method may furtherinclude, prior to step a), a step at). Step at) is oxidative coupling ofmethane or oxidative dehydrogenation of hydrocarbons at hydrocarbonoxidation reaction conditions to produce the first process stream. Thehydrocarbon reaction conditions are understood to be different from thereaction conditions to carry out the oxidation of the CO to the CO₂.Stepat) is oxidative coupling of methane or oxidative dehydrogenation ofhydrocarbons at hydrocarbon oxidation reaction conditions. For example,the step at) takes place at higher temperatures than step a). The stepat) oxidative coupling of methane or oxidative dehydrogenation ofhydrocarbons takes place at temperatures of 750° C. to 850° C. or evenhigher. The step a) oxidation of CO to CO₂ is done at considerably lowertemperatures, for example, from 350° C. to 450° C., or from 250° C. to500° C., or from 200° C. to 400° C., or from 350° C. to 500° C.

According to another embodiment of the invention, the oxygen transferagent that is used to carry out the conversion of CO to CO₂ may be i)water and the step a1) oxidative coupling of methane or oxidativedehydrogenation of hydrocarbons produces the water that is used as theoxygen transfer agent in step a). According to an embodiment of theinvention, step at) and step a) may be performed in the same reactor. Inthis case, the water produced as a side product is therefore used tocarry out the oxidation of the CO to the CO₂. Appropriate catalysts maybe used for this oxidation of the CO to CO₂ using water as the oxidant,according to some embodiments.

According to another embodiment, the oxygen transfer agent used toconvert the CO to CO₂ may be at least one of ii) at least one reduciblemetal oxide or iii) at least one reducible chalcogen and the same oxygentransfer agent ii) or iii) may be used in step at) and step a).According to this embodiment, the reaction conditions during the CO toCO₂ conversion step a) are different from the reaction conditions duringthe ODH reaction of step at). It is important that the conditions ofstep a) do not further oxidize the mixed at least one of C1 to C12saturated and unsaturated hydrocarbons. According to an embodiment ofthe invention, step at) and step a) may be performed in the samereactor. This is done by changing reaction conditions such that thehydrocarbon feed stream reactor is first oxidatively dehydrogenated asstep at), and then adjusting the reaction conditions such that the COproduced in step a1) is converted to CO₂ in step a), without furtheroxidizing the hydrocarbons in the reactor.

According to an embodiment, the step a) takes place in the presence ofless than 5 wt % of O₂ with respect to the total amount of CO in thefirst process stream. According to some embodiments the amount of oxygenin the first process stream is at most 5 wt %, or at most 4.8, 4.6, 4.4,4.2, 4, 3.8, 3.6, 3.4, 3.2, 3, 2.8, 2.6, 2.4, 2.2, 2, 1.8, 1.6, 1.4,1.2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or at most 0.1 wt % ofO₂ with respect to the total amount of CO in the first process stream.According to some embodiments there is at most 950 ppm wt, or at most900, 850, 800, 750, 700, 650, 600, 550, 500, 450, 400, 350, 300, 250,200, 150, 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 5, 1, 0.5, or 0.1 ppmwt O₂ with respect to the total amount of CO in the first processstream. According to an embodiment, there is no O₂ in the first processstream.

According to an embodiment, the oxygen transfer agent is the reduciblemetal oxide ii) and/or the reducible chalcogen iii) and the methodfurther comprises a step c) contacting the reduced oxygen transfer agentwith a third process stream comprising molecular oxygen to provide aregenerated oxygen transfer agent.

According to an embodiment, the method further comprises a step d)feeding the regenerated oxygen transfer agent to step a) as the oxygentransfer agent.

According to another embodiment, the method further comprises a step d)feeding the regenerated oxygen transfer agent to step a) converting theCO to CO₂ and/or to step a1) the ODH reaction as the oxygen transferagent.

According to an embodiment, the method further comprises a step e)removing at least a portion of the CO₂ from the second process stream.This removal may be done according to methods as are known in the art,such as amine extraction, membrane separation, cryogenic separation andthe like.

According to another embodiment of the method of converting the CO toCO₂, the oxygen transfer agent is i) water and the reduced oxygentransfer agent comprises H₂. This method may optionally be performed inthe presence of suitable catalysts, such as those based on Mn, Fe, Cu,Zn, Ce, Cr, Co, Ni, oxides thereof; rare earth oxides; and/orcombinations of any of the forgoing, for example.

Method of Converting CO to CH₄

According to another embodiment of the invention, the CO is removed byconverting it to methane, CH₄. A method of converting CO to CH₄ isprovided. The method comprises, consists of, or consists essentially of:

a) contacting a first process stream comprising the CO and at least oneC1 to C12 saturated and unsaturated hydrocarbons with a hydrogenationcatalyst and a source of H₂; and

b) reacting at least a portion of the CO with the H₂, at reactionconditions, to provide a second process stream comprising the CH Stepat) is oxidative coupling of methane or oxidative dehydrogenation ofhydrocarbons at hydrocarbon oxidation reaction conditions and water.Importantly in this method, the at least one of C1 to C12 unsaturatedhydrocarbons in the first process stream are not reduced in step b). Thefirst process stream comprising the CO is a hydrocarbon product streamresulting from the oxidative coupling of methane or oxidativedehydrogenation of hydrocarbons. Therefore, it is clearly desirable forthe valuable unsaturated products in the first process stream to not bereduced back to saturated hydrocarbons. Accordingly, the reactionconditions, such as suitable gas hourly space velocities, pressures andtemperatures are selected so as to avoid this. Suitable catalysts may beused to hydrogenate the CO to methane. Non-limiting examples arePd/Al₂O₃, Cr, Zn, etc. According to an exemplary embodiment, the CO tomethane process may be carried out in two stages: over a chromiumcatalyst at high temperature (300-560° C.) which gets CO concentrationsdown to 2-3%. The second stage may use Cu/Zn oxide with alumina, at200-260° C.

Systems for Oxidatively Converting CO to CO₂:

A system for oxidatively converting CO to CO₂ is provided. The systemcomprises, consists of, or consists essentially of:

at least one reactor configured for:

a) contacting a first process stream comprising the CO and at least oneof C1 to C12 saturated and unsaturated hydrocarbons with an oxygentransfer agent; and

b) oxidizing at least a portion of the CO to CO₂, at reactionconditions, and reducing at least a portion of the oxygen transfer agentto provide a second process stream comprising the CO₂, the reducedoxygen transfer agent, and the at least one of C1 to C12 saturated andunsaturated hydrocarbons; wherein the at least one of C1 to C12saturated and unsaturated hydrocarbons are not further oxidized. Theoxygen transfer agent comprises, comprises, consists of or consistsessentially of at least one of:

i) water; ii) at least one reducible metal oxide; iii) at least onereducible chalcogen; or any combination of two or more of i), ii), andiii).

According to an embodiment, the first process stream is produced by astep at) comprising, consisting of, or consisting essentially ofoxidative coupling of methane or oxidative dehydrogenation ofhydrocarbons at hydrocarbon oxidation reaction conditions.

According to an embodiment, the oxygen transfer agent is i) water andthe step at) produces water that is used as the oxygen transfer agent instep a). According to an embodiment of the system, step at) and step a)are performed sequentially in the same reactor. According to anembodiment, the oxygen transfer agent is ii) or iii) and the step at)utilizes the same oxygen transfer agent ii) as step a).

According to an embodiment of the system, the oxygen transfer agentcomprises, consists of, or consists essentially of ii), iii) or acombination thereof and the at least one reactor comprises an inlet andan outlet. The system further comprises, consists of, or consistsessentially of a regeneration unit in communication with the inlet andthe outlet, wherein the regeneration unit is constructed and arrangedto:

c) receive at least a portion of the reduced oxygen transfer agent fromthe outlet;

d) contact the at least a portion of the reduced oxygen transfer agentwith a gas comprising molecular oxygen to produce a regenerated oxygentransfer agent; and

e) feed the regenerated oxygen transfer agent to the inlet.

According to an embodiment, the system further comprises, consists of,or consists essentially of a purification unit in communication with theat least one reactor, wherein the purification unit is constructed andarranged to remove at least a portion of the CO₂ from the second processstream. This purification unit may be an amine or other base absorber, acryogenic distillation unit, a caustic wash, or a membrane separationunit, for example.

Systems for Converting CO to CH₄:

A system for converting CO to CH₄ is provided. The system comprises,consists of or consists essentially of:

at least one reactor configured for:

a) contacting a first process stream comprising, consisting of, orconsisting essentially of the CO and at least one C1 to C12 saturatedand unsaturated hydrocarbons with a hydrogenation catalyst and a sourceof H₂; and

b) reacting at least a portion of the CO with the H₂, at reactionconditions, to provide a second process stream comprising, consistingof, or consisting essentially of the CH₄ and water;

wherein the at least one of C1 to C12 unsaturated hydrocarbons are notreduced in step b); and

wherein the first process stream comprising the CO is a hydrocarbonproduct stream resulting from the oxidative coupling of methane oroxidative dehydrogenation of hydrocarbons.

Reactors:

The reactors employed in certain embodiments of the system or methoddirected to the use of an oxygen transfer agent (OTA) for the in-streamoxidation of CO to CO₂ as described herein could be any system known totransport a solid particle between a reactor and a regenerator zone.Such transport systems are generally known to one of ordinary skill inthe art. While not intending to be limited by these examples, usefulreactors are circulating fluid beds such as fluid catalyzed crackingunits, fluidized bed reactors, moving bed reactors, either co-current orcounter current flow and bubbling bed reactors with means of transportof solids between the beds, or any circulating system as known in theart. The reactors could also be fixed, or non-circulating fluid bed,reactors whereby reaction gases are switched at appropriate timesbetween oxidation conditions and re-oxidation conditions.

Regeneration Units:

Suitable regeneration units utilized in the system or method disclosedin the first embodiment herein to re-oxidize the reduced oxygen transferagent may be any of those types as known and used in the art toregenerate solid particulates, especially, but not limited to those thatare suitable for contacting a particulate solid with a gas. For example,fluidized beds, rotating moving beds, recirculating fluidized beds,moving beds, either co-current or counter current flow and bubbling bedswith means of transport of solids between the beds, or any circulatingsystem as known in the art may be used to regenerate the oxygen transferagent. The regeneration reactors could also be fixed, or non-circulatingfluid bed, reactors whereby reaction gases are switched at appropriatetimes between oxidation conditions and re-oxidation conditions.

Reaction Conditions for the Oxidative Conversion of CO to CO₂:

According to some embodiments of the system and method, one or more ofthe reactor conditions to carry out the oxidative conversion of CO toCO₂ with a selective OTA in the presence of the hydrocarbon product fromOCM or ODH.

According to some embodiments, the reaction conditions for the use ofOTA to convert CO to CO₂ may include the presence of essentially nomolecular oxygen during the oxidative conversion of CO. In thisembodiment, at least a portion of the oxygen transfer agent may bereduced to produce a reduced oxygen transfer agent. Without wishing tobe bound by theory, this condition means that the oxygen needed for theoxidative conversion of CO may be supplied by the at least one oxygentransfer agent.

According to other embodiments, molecular oxygen may be present duringthe oxidative conversion of CO to CO₂. In particular, less than 5 wt %,less than 4 wt %, less than 3 wt %, less than 2 wt %, less than 1 wt %,less than 0.5 wt %, less than 1000 ppm weight, less than 500 ppm weightof molecular oxygen with respect to the total amount of CO in the firstprocess stream, the oxygen transfer agent and the molecular oxygen ispresent during the CO oxidative conversion step. Less than 1000 ppmweight of molecular oxygen is preferred. Non-limiting examples ofsources of molecular oxygen are air, or molecular oxygen-containingstreams resulting from other chemical processes.

According to some embodiments the oxidative reaction conditions in stepb) may include temperatures of from 325-650° C. and gas hourly spacevelocities of 1,000 to 10,000 hr⁻¹. Other suitable temperatures may befrom 300° C. to 1000° C., 350° C. to 1000° C., 400° C. to 1000° C., 400°C. to 800° C., or from 500° C. to 700° C. Pressure may be fromsub-atmospheric to super-atmospheric with a range of 0.1 to 100 atm. Inother embodiments, the pressure range may be 0.9 to 10 atm. Otherpressure ranges may be from 0.9 to 1.5, 0.5 to 2, 0.9 to 5, 0.9 to 7, or0.9 to 1.1 atm. According to some embodiment, the temperature may befrom 600-950° C., or from 500-900° C. or from 700-900° C. or from800-850° C. For example the temperature may be at least 250° C., or atleast 300, 325, 350, 400, 400, 450, 500, 550, 600, 650, 700, or at least750° C. For example, the temperature may be at most 1000° C., or at most950, 900, 850, 800, 750, 700, or at most 650° C.

While in some cases it might be desirable to separate the feedcomponents before introduction to the reactor vessel, it may also bebeneficial not to separate some of the hydrocarbons and allow thereactor conditions to effect separation. In this instance of the presentinventive system or method, as an example, methane and ethane could befed to one reactor zone where ethane primarily reacts at one set ofreactor conditions to form olefin products and then separation occursbetween the unreacted methane and olefins formed from ODH.

In another embodiment of the present system or method, multiple reactorsmay be used to selectively feed hydrocarbons for oxidativedehydrogenation under appropriate conditions to form olefins and otherreactors under different conditions to oxidatively convert CO to CO₂.According to certain embodiments of the system or method, the feature ofmultiple reactors utilizing a single regeneration unit can allow for asingle OTA to be used for both hydrocarbon ODH or OCM and other reactorsto be used for CO oxidation, the multiple reactors allowing foroptimization of reaction conditions for each conversion.

In another embodiment of the present system and method, CO is convertedto CO₂ and hydrogen in the presence of steam similar to the well-knownWater Gas Shift (WGS) process and may be performed either with, orwithout a catalyst. In this embodiment, the oxidation transfer agent iswater, and it is reduced to H₂. While not to be limited by theory, thematerials and catalysts for this process of converting CO to CO₂ couldbe any materials typically used for WGS such as catalysts comprising,iron, zinc, nickel, rhodium, iridium, platinum, palladium, gold,ruthenium, or other metals useful for the WGS reaction. A key aspect forthe use of WGS for CO removal is that it operates above 300° C. andimportantly does not also co-produce oxygenated products such asalcohols or acetic acid, or aldehydes during the WGS separation process.Oxygenated products such as these, if formed during the CO removalprocess may add greatly to the cost for recovery of polymer gradeolefins. In addition, low alcohol content in polymer grade ethylene isgenerally required in order not to be a poison for typicalpolymerization catalysts.

Reactions:

The systems disclosed in the present invention may be used for theremoval of CO by-products from the oxidative dehydrogenation ofhydrocarbon feeds that may proceed according to the reaction:

zCnH_(2n+2−2β)+(z−1+δ)“O”→C_((z×n))H_(2(z×n)+2−2β−2δ)+(z−1+δ)H₂O

wherein: z=the number of reactant molecules; n=the number of atomicunits in the reactant molecule; β=the degree of unsaturation in thereactant molecule, where the value is zero for single bonds, and one fordouble bonds and molecular rings; 6=the change in the degree ofunsaturation from the reactant molecule to the product molecule; and “O”is atomic oxygen; and wherein the atomic oxygen is supplied by the atleast one oxygen transfer agent. According to some embodiments, z=2,n=1, β=0, and δ=0. In particular this means that the reaction mayinclude the oxidative coupling of methane to form ethylene. According toother embodiments, z=1, n=2, β=0, and δ=1. In particular, this meansthat the reaction may include the oxidative dehydrogenation of ethane toform ethylene. The oxidative dehydrogenation may include more than onereaction. Non-limiting examples of such multiple reactions may include:skeletal isomerization of olefins; oxidative dehydrogenation of methaneto ethane and ethylene, and oxidative dehydrogenation of ethane toethylene and higher olefins such as propylene and butylene.

CO and CO₂ are generally also produced in the oxidative dehydrogenationsystems and must be efficiently removed. In one embodiment of thepresent disclosure, CO is oxidized to CO₂ using an OTA/redox cycle as inequations 1 and 2. In another embodiment, the oxidation of CO may usemolecular oxygen

CO+½O₂→CO₂

In yet another embodiment, CO is reacted with steam and converted to CO₂and hydrogen with or without a catalyst.

CO+H₂O

CO₂+H₂

Hydrocarbon Feed:

Suitable mixed hydrocarbon feeds for use in embodiments of the presentsystem or method invention may be selected from methane; ethane;propane; isomers of butane; isomers of butene, isomers of pentane;isomers of pentene; isomers of hexane; cyclohexane; isomers of hexene;cyclohexene; naphtha; gas oil; and mixtures thereof. As used here, theterm “mixed hydrocarbon feed” means a feed including two or moredifferent hydrocarbons, for example a feed stream containing methane andethane.

Oxygen Transfer Agents:

Non-limiting examples of suitable oxygen transfer agents for use inembodiments of the present invention may include at least one elementselected from the group consisting of, Mn, Fe, Mo, Ti, V, Pr, Cu, La, Gaand mixtures thereof. A suitable oxygen transfer agent may includeLi/Mn/B/MgO, Li/Mn/B/CaSO₄/MgO, Na/Pr₆O₁₁, and mixtures thereof. In anembodiment, the oxygen transfer agent may further include at least onepromotor selected from the group consisting of, alkaline metals,alkaline earth metals, boron, sulfur, salts of tungstic acid, salts ofhalides, and mixtures thereof. Other suitable oxygen transfer agentsthat may be used in embodiments of this invention are those that aredescribed in United States patent application Nos. U.S. Ser. No.16/800,883 filed on Feb. 25, 2020; U.S. Ser. No. 16/845,815 filed onApr. 10, 2020; and U.S. Ser. No. 16/877,992 filed May 20, 2020, thecontents of each of which are incorporated by reference herein in theirentireties for all purposes.

For example, the oxygen transfer agent for converting CO to CO₂ may beat least one reducible metal oxide that comprises, consists of, orconsists essentially of at least one of alkaline earth metals, actinidemetals, lanthanide metals trivalent transition metals, or combinationsthereof. The at least one reducible metal oxide may comprise, consistof, or consist essentially of at least one of Li/Mn/B/MgO,Li/Mn/B/CaSO₄/MgO, Na/Pr₆₀₁₁, Mn, Fe, Mo, Ti, V, Pr, Cu, La, Ga, Tb, Nd,Dy, or mixtures or combinations thereof. Suitable such materials aredescribed in U.S. Pat. No. 11,046,892, the contents of which isincorporated by reference herein in its entirety for all purposes.

According to certain embodiments, any of the reducible metal oxides ii)or reducible chalcogens iii) used to convert CO to CO₂ as describedherein may be in combination with at least one zeolite, such that innerchannels of the at least one zeolite are from 3 to 8 Angstroms in size.The zeolite may be acidic in nature and the acid nature may be confinedto the exterior surfaces of the zeolite. If present, the zeolite maycomprise, consist of, or consist essentially of zeolite Y, ZSM-5. Thereducible metal oxides ii) or reducible chalcogens iii) may comprise,consist of, or consist essentially of oxides of Mn, oxides of Cu, and/oroxides of Ca. According to certain embodiments the oxygen transfer agentii) or iii) that is used to convert the CO to CO₂ may comprise, consistof, or consist essentially of at least one oxide of sulfur selected fromsulfur dioxide; sulfur trioxide; CaSO₄; sulfate salts of Mn, Fe, Sm, Ga,Ti, W, Mo, V, Nb, Cr, K, Cs, Rb, P, Cu, Pb, Ni, As; or mixtures thereof.According to an embodiment, the at least one oxygen transfer agent ii)or iii) used to convert the CO to CO₂ may be selected from MnO₂, CuO, orCaO. According to an embodiment, the reducible metal oxide ii) mayinclude at least one oxide of sulfur selected from sulfur dioxide;sulfur trioxide; CaSO₄; sulfate salts of Mn, Fe, Sm, Ga, Ti, W, Mo, V,Nb, Cr, K, Cs, Rb, P, Cu, Pb, Ni, and As; and mixtures thereof.According to an embodiment, the at least one oxygen transfer agent ii)or iii) used to convert the CO to CO₂ may be selected from MnO₂, CuO, orCaO. According to an embodiment, the reducible metal oxide ii) may beselected from oxides of La, oxides of Pr, oxides of Tb, oxides of Nd,oxides of Dy, or mixtures thereof.

According to another embodiment, the oxygen transfer agent ii) forconverting CO to CO₂ may comprise, comprises, consist of, or consistessentially of at least one reducible metal oxide ii) that comprises,consists of, or consists essentially of at least one of M₃BO₅, acompound that satisfies the formula M′2M″BO₅, or mixtures thereof. M isselected from alkaline earth metals, actinide metals, lanthanide metals,trivalent transition metals, and combinations thereof; M′ is selectedfrom alkaline earth metals, actinide metals, lanthanide metals, andcombinations thereof; and M″ is selected from the group consisting of,trivalent transition metals, and combinations thereof. According to anembodiment, M′ may be selected from Mg, Ca, Sr, Ba, and mixturesthereof. According to an embodiment, M″ may be selected from Mn, Fe, Co,Cu, V, Nb, Ta, Cr, Mo, W, and mixtures thereof. According to anembodiment, the compound that satisfies the formula M₃BO₅ may beselected from the ludwigite class minerals, and combinations thereof.The ludwigite class mineral may be selected from pinakiolite,orthopinakiolite, takeuchiite, fredrikssonite, and combinations thereof.The at least one oxygen transfer agent ii) may further comprises amagnesia-phosphate cement that satisfies the formula: MgM′″PO₄.mH₂O;wherein M′″ is selected from sodium, lithium, potassium, and mixturesthereof; and m is an integer from 0 to 6. According to an embodiment,the magnesia-phosphate cement may comprise, consist of, or consistessentially of at least one of MgKPO₄.mH₂O and MgNaPO₄.mH₂O, wherein mis an integer from 0 to 6. According to an embodiment, the metal-boronoxide may comprise, consist of or consist essentially of Mg₂MnO₂(BO₃)and the magnesia-phosphate cement may comprise, consist of, or consistessentially of NaMg(PO₄).mH₂O. According to another embodiment, that atleast one oxygen transfer agent ii) may further comprise at least onepromotor selected from alkali metals, alkaline earth metals, andmixtures thereof. If present, the at least one promoter may be selectedfrom Li₂WO₄, Na₂WO₄, K₂WO₄, SrWO₄, Li₂MoO₄, Na₂MoO₄, K₂MoO₄, CsMoO₄,Li₂CO₃, Na₂CO₃, K₂CO₃, CaSO₄, Na₂SO₄, NaHSO₄, and mixtures thereof.Suitable such materials are described in U.S. Pat. No. 10,919,027, thecontents of which is incorporated by reference herein in its entiretyfor all purposes.

According to another embodiment, the oxygen transfer agent forconverting CO to CO₂ may comprise, consist of or consist essentially ofat least one reducible metal oxide ii) comprising, consisting of, orconsisting essentially of a metal-boron oxide; and a magnesia-phosphatecement. The average oxidation state of the metal in the metal-boronoxide may be from 2.7+ to less than 4.0+, and the oxygen transfer agentmay comprise, consist of, or consist essentially of 10% or less of astoichiometric excess of Mn with respect to the boron. Themagnesia-phosphate cement comprises, consists of, or consistsessentially of MgM′″PO₄.mH₂O, wherein m is an integer from 0 to 6; andwherein the metal-boron oxide comprises at least one compound thatsatisfies the formula M′2M″BO₅, wherein M′ is selected from one or moreof alkaline earth metals, actinide metals, lanthanide metals, andcombinations thereof; and M″ is selected from one or more of trivalenttransition metals. According to an embodiment, the reducible metal oxideii) may comprise 10 wt % or less of Mg₆MnO₈. According to an embodiment,the reducible metal oxide ii) may comprise 5 wt % or less of Mg₆MnO₈.The compound that satisfies the formula M₃BO₅ may be selected from theludwigite class minerals, and combinations thereof. These ludwigiteclass minerals may be selected from pinakiolite, orthopinakiolite,takeuchiite, fredrikssonite, and combinations thereof. According to anembodiment, M′ may be selected from Mg, Ca, Sr, Ba, and mixtures thereofand M″ may be selected from Mn, Fe, Co, Cu, V, Nb, Ta, Cr, Mo, W, andmixtures thereof. The magnesia-phosphate cement may comprise, consistof, or consist essentially of at least one of MgKPO₄.mH₂O andMgNaPO₄.mH₂O, wherein m is an integer from 0 to 6. According to anembodiment, the metal-boron oxide comprises Mg₂MnO₂(BO₃). Themagnesia-phosphate cement may comprise, consist of, or consistessentially of NaMg(PO₄).mH₂O. According to an embodiment, M′″ may beselected from sodium, lithium, potassium, and mixtures thereof.According to an embodiment, the reducible metal oxide ii) may furtherinclude at least one promotor selected from alkali metals, alkalineearth metals, and mixtures thereof. The at least one promoter mayselected from Li₂WO₄, Na₂WO₄, K₂WO₄, SrWO₄, Li₂MoO₄, Na₂MoO₄, K₂MoO₄,CsMoO₄, Li₂CO₃, Na₂CO₃, K₂CO₃, CaSO₄, Na₂SO₄, NaHSO₄, and mixturesthereof. Suitable such oxygen transfer agents are described in detail inU.S. Pat. No. 11,192,092, the entire contents of which is incorporatedby reference herein in its entirety for all purposes.

According to an embodiment, the reducible metal oxide ii) used toconvert the CO to CO₂ may comprise, consist of, or consist essentiallyof a mixed oxide which is Mg₆MnO₈, and at least two promoters whichinclude W and P. The reducible metal oxide ii) of this embodiment mayfurther comprise, consist of, or consist essentially of an alkali metalor compounds thereof. The reducible metal oxide may further includeboron or compounds thereof. The reducible metal oxide ii) of thisembodiment may further comprise, consist of, or consist essentially ofan oxide of an alkaline earth metal. The reducible metal oxide ii) ofthis embodiment may further include an oxide of manganese, wherein themanganese has a valence state selected from 4+, 3+, 8/3+, and 2+. Thereducible metal oxide ii) of this embodiment may further comprise,consist of, or consist essentially of at least one of NaB₂Mg₄Mn₂O₄,NaB₂Mn₂Mg₄O_(11.5), NaMn₂O₄, LiMn₂O₄, Mg₃Mn₃B₂O₁₀, Mg₃(BO₃)₂, and anon-crystalline compound comprising oxygen and at least one of sodium,boron, magnesium, manganese, and lithium. Details of this embodiment ofthe reducible metal oxide ii) used as the oxygen transfer agent toconvert CO to CO₂ may be found in U.S. Pat. No. 10,138,182, the entiredisclosure of which is incorporated by reference herein for allpurposes.

According to another embodiment, the oxygen transfer agent forconverting the CO to CO₂ comprises, consists of, or consists essentiallyof iii) a reducible chalcogen. According to an embodiment, the reduciblechalcogen comprises, consists of or consists essentially of:

(A) 10 to 90 wt % CaSO₄;

(B) 1 to 85 wt % of a total of W and at least one of Fe and/or Mn; and

(C) 1 to 10 wt % of an alkali metal salt.

According to an embodiment, (B) is W and Fe. According to anotherembodiment, (B) is W and Mn. According to yet another embodiment, (B) isW, Fe, and Mn. According to an embodiment, (B) may be W and Fe and (C)may be an alkali metal halide. According to another embodiment, (B) maybe W and Fe, and (C) may be an alkali metal hydroxide. According to anembodiment, (B) may be W and Mn, and (C) may be an alkali metal halide.According to an embodiment, (B) may be W and Mn, and (C) may be analkali metal hydroxide. According to an embodiment, (B) may be W, Fe andMn, and (C) may be an alkali metal halide. According to yet anotherembodiment, (B) may be W, Fe and Mn, and (C) may be an alkali metalhydroxide. Suitable such materials are described in detail in U.S. Pat.No. 11,104,625, the entire contents of which are incorporated byreference herein in its entirety for all purposes.

According to another embodiment of the invention, the oxygen transferagent for converting the CO to CO₂ may be a reducible metal oxide ii)and a reducible chalcogen iii) and may comprise, consist of, or consistessentially of at least one of a sulfate salt of an alkaline earth metalor a sulfate salt of an alkali metal, and a sulfate salt of manganese.The chalcogen agent iii) has an oxidation state greater than +2. Thereducible (oxygen-donating) chalcogen agent iii) and the reducible metaloxide ii) are in solid form. According to an embodiment, the oxygentransfer agent for converting CO to CO₂ comprises, consists of orconsists essentially of Mg₆MnO₈ and at least one promoter selected fromSm, Ga, Ti, W, Mo, V, Nb, Cr, K, Cs, Rb, P, Cu, Pb, Ni and As. Accordingto another this oxygen transfer agent further comprises boron or atleast one compound thereof. According to an embodiment, the oxygentransfer agent may additionally comprise at least one alkali metal or acompound thereof. According to another embodiment this the oxygentransfer agent may additionally comprise at least one of an alkali metaloxide or an alkaline earth metal oxide. According to an embodiment, thisoxygen transfer agent may comprise a manganese oxide and the manganesemay have a valence state of 4+, 3+, 8/3+, or 2+. According to anembodiment, the oxygen transfer agent may comprise, consist of orconsist essentially of at least one compound selected from NaB₂Mg₄Mn₂O₄,NaB₂Mn₂Mg₄O_(11.5), NaMn₂O₄, LiMn₂O₄, Mg₃Mn₃B₂O₁₀, Mg₃(BO₃)₂, and anon-crystalline compound including oxygen and at least one of sodium,boron, magnesium, manganese, or lithium. According to anotherembodiment, the reducible metal oxide ii) may be ionically andelectronically conductive. According to another embodiment, thereducible chalcogen iii) comprises, consists of, or consists essentiallyof calcium sulfate. According to an embodiment, a chalcogen of thereducible chalcogen iii) has an oxidation state of +3 to +6. Accordingto another embodiment, the reducible chalcogen iii) has an oxidationstate greater than +3 and less than +6. According to an embodiment, thechalcogen iii) has an oxidation state of +4. According to anotherembodiment, this oxygen transfer agent for converting CO to CO₂ furthercomprises, consists of or consists essentially of a sulfate salt of Sm,Ga, Ti, W, Mo, V, Nb, Cr, K, Cs, Rb, P, Cu, Pb, Ni, or As. Details ofthese embodiments of the oxygen transfer reagent for converting CO toCO₂ are described in detail in U.S. Pat. No. 10,968,149, the contents ofwhich is incorporated by reference herein in their entirety for allpurposes.

Non-limiting aspects of the invention may be summarized as follows:

Aspect 1: A method of converting CO to CO₂ comprising,

a) contacting a first process stream comprising the CO and at least oneof C1 to C12 saturated and unsaturated hydrocarbons with an oxygentransfer agent; and

b) oxidizing at least a portion of the CO to CO₂ and reducing at least aportion of the oxygen transfer agent to a reduced oxygen transfer agent,at reaction conditions, to provide a second process stream comprisingthe CO₂, the reduced oxygen transfer agent, and the at least one of C1to C12 saturated and unsaturated hydrocarbons; wherein the C1 to C12saturated and unsaturated hydrocarbons are not further oxidized; and

wherein the oxygen transfer agent comprises at least one of:

i) water; ii) at least one reducible metal oxide; iii) at least onereducible chalcogen; mixtures of any combination of two or more of i),ii), and iii).

Aspect 2: The method of Aspect 1, further comprising, prior to step a),performing a step at) comprising oxidative coupling of methane oroxidative dehydrogenation of hydrocarbons at hydrocarbon oxidationreaction conditions to produce the first process stream.

Aspect 3: The method of either Aspect 1 or Aspect 2 wherein the oxygentransfer agent comprises i) water and the step at) produces the waterthat is used as the oxygen transfer agent in step a).

Aspect 4: The method of any of Aspects 1-3, wherein step at) and step a)are performed in the same reactor.

5: The method of Aspect 1 or Aspect 2, wherein the oxygen transfer agentcomprises ii) or iii) and the same oxygen transfer agent ii) or iii) isused in step at) and step a).

Aspect 6: The method of Aspect 5, wherein step a1) and step a) areperformed in the same reactor.

7. The method of any of Aspects 1-6, wherein the oxygen transfer agentcomprises ii) and the at least one reducible metal oxide comprises atleast one of alkaline earth metals, actinide metals, lanthanide metalstrivalent transition metals, or combinations thereof.

Aspect 8: The method of any of Aspects 1-7, wherein the oxygen transferagent comprises ii) and the at least one reducible metal oxide comprisesat least one of Li/Mn/B/MgO, Li/Mn/B/CaSO₄/MgO, Na/Pr₆O₁₁, Mn, Fe, Mo,Ti, V, Pr, Cu, La, Ga, Tb, Nd, Dy, or mixtures or combinations thereof.

Aspect 9: The method of any of Aspects 1-8, wherein the oxygen transferagent comprises ii) and the reducible metal oxide comprises at least oneof M₃BO₅, a compound that satisfies the formula M′2M″BO₅, or mixturesthereof; and

wherein M is selected from the group consisting of, alkaline earthmetals, actinide metals, lanthanide metals, trivalent transition metals,and combinations thereof; M′ is selected from the group consisting of,alkaline earth metals, actinide metals, lanthanide metals, andcombinations thereof; and M″ is selected from group consisting of,trivalent transition metals, and combinations thereof.

Aspect 10: The method of any of Aspects 1-9, wherein the oxygen transferagent comprises ii) and the reducible metal oxide comprises ametal-boron oxide; and

a magnesia-phosphate cement;

wherein:

the average oxidation state of the metal in the metal-boron oxide isfrom 2.7+ to less than 4.0+, and the oxygen transfer agent comprises 10%or less of a stoichiometric excess of Mn with respect to the boron; and

the magnesia-phosphate cement comprises: MgM′″PO₄.mH₂O, wherein m is aninteger from 0 to 6; and

wherein the metal-boron oxide comprises at least one compound thatsatisfies the formula M′2M″BO₅,

wherein M′ is selected from one or more of alkaline earth metals,actinide metals, lanthanide metals, and combinations thereof; and M″ isselected from one or more of trivalent transition metals.

Aspect 11: The method of any of Aspects 1-10, wherein the oxygentransfer agent comprises iii) and the reducible chalcogen comprises:

(A) 10 to 90 wt % CaSO₄;

(B) 1 to 85 wt % of a total of W and at least one of Fe and/or Mn; and

(C) 1 to 10 wt % of an alkali metal salt.

Aspect 12: The method of any of Aspects 1-11, wherein the oxygentransfer agent comprises ii) and the reducible metal oxide furthercomprises at least one promotor comprising at least one of alkalinemetals, alkaline earth metals, boron, sulfur, salts of tungstic acid,salts of halides, or mixtures thereof.

Aspect 13: The method of any of Aspects 1-12, wherein the step a) takesplace in the presence of less than 5 wt % of O₂ with respect to thetotal amount of CO in the first process stream.

Aspect 14: The method of any of Aspects 1-13, wherein the oxygentransfer agent comprises ii) or iii) and the method further comprises astep c) contacting the reduced oxygen transfer agent with a thirdprocess stream comprising molecular oxygen to provide a regeneratedoxygen transfer agent.

Aspect 15: The method of any of Aspects 1-14, wherein the method furthercomprises a step d) feeding the regenerated oxygen transfer agent tostep a) as the oxygen transfer agent.

Aspect 16: The method of any of Aspects 1-15, wherein the oxygentransfer agent comprises ii) or iii) and the method further comprises astep c) contacting the reduced oxygen transfer agent with a thirdprocess stream comprising molecular oxygen to provide a regeneratedoxygen transfer agent.

Aspect 17: The method of Aspect any of Aspects 1-16, wherein the methodfurther comprises a step d) feeding the regenerated oxygen transferagent to step a) and/or to step at) as the oxygen transfer agent.

Aspect 18: The method of any of Aspects 1-17, wherein the method furthercomprises a step e) removing at least a portion of the CO₂ from thesecond process stream.

Aspect 19: The method of any of Aspects 1-19, wherein the oxygentransfer agent comprises i) water and the reduced oxygen transfer agentcomprises H₂.

Aspect 20: A system for oxidatively converting CO to CO₂ comprising:

at least one reactor configured for:

a) contacting a first process stream comprising the CO and at least oneof C1 to C12 saturated and unsaturated hydrocarbons with an oxygentransfer agent; and

b) oxidizing at least a portion of the CO to CO₂, at reactionconditions, and reducing at least a portion of the oxygen transfer agentto provide a second process stream comprising the CO₂, the reducedoxygen transfer agent, and the at least one of C1 to C12 saturated andunsaturated hydrocarbons; wherein the at least one of C1 to C12saturated and unsaturated hydrocarbons are not further oxidized; and

wherein the oxygen transfer agent comprises at least one of:

i) water; ii) at least one reducible metal oxide; iii) at least onereducible chalcogen; any combination of two or more of i), ii), andiii).

Aspect 21: The system of Aspect 20, wherein the first process stream isproduced by a step at) comprising oxidative coupling of methane oroxidative dehydrogenation of hydrocarbons at hydrocarbon oxidationreaction conditions.

Aspect 22: The system of Aspect 20 or Aspect 21, wherein the oxygentransfer agent comprises i) water and the step at) produces water thatis used as the oxygen transfer agent in step a).

Aspect 23: The system of Aspect 21 or Aspect 22, wherein step at) andstep a) are performed sequentially in the same reactor.

Aspect 24: The system of any of Aspects 21-23, wherein the oxygentransfer agent comprises ii) or iii) and the step at) utilizes the sameoxygen transfer agent ii) as step a).

Aspect 25: The system of Aspect 24, wherein step at) and step a) areperformed sequentially in the same reactor.

Aspect 26: The system of any of Aspects 20-25, wherein the oxygentransfer agent comprises ii) or iii) and the at least one reactorcomprises an inlet and an outlet, and wherein the system furthercomprises a regeneration unit in communication with the inlet and theoutlet, wherein the regeneration unit is constructed and arranged to:

c) receive at least a portion of the reduced oxygen transfer agent fromthe outlet;

d) contact the at least a portion of the reduced oxygen transfer agentwith a gas comprising molecular oxygen to produce a regenerated oxygentransfer agent; and

e) feed the regenerated oxygen transfer agent to the inlet.

Aspect 27: The system of any of Aspects 20-26, wherein the systemfurther comprises a purification unit in communication with the at leastone reactor, wherein the purification unit is constructed and arrangedto remove at least a portion of the CO₂ from the second process stream.

28: The system of any of Aspects 20-27, wherein the oxygen transferagent comprises ii) and the at least one reducible metal oxide comprisesat least one of alkaline earth metals, actinide metals, lanthanidemetals trivalent transition metals, or combinations thereof.

Aspect 29: The system of any of Aspects 20-28, wherein the oxygentransfer agent comprises ii) and the at least one reducible metal oxidecomprises at least one of Li/Mn/B/MgO, Li/Mn/B/CaSO₄/MgO, Na/Pr₆O₁₁, Mn,Fe, Mo, Ti, V, Pr, Cu, La, Ga, Tb, Nd, Dy, or mixtures or combinationsthereof.

30: The system of Aspect any of Aspects 20-29, wherein the oxygentransfer agent comprises ii) and the reducible metal oxide comprises atleast one of M₃BO₅, a compound that satisfies the formula M′₂M″BO₅, ormixtures thereof; and

wherein M is selected from the group consisting of, alkaline earthmetals, actinide metals, lanthanide metals, trivalent transition metals,and combinations thereof; M′ is selected from the group consisting of,alkaline earth metals, actinide metals, lanthanide metals, andcombinations thereof; and M″ is selected from group consisting of,trivalent transition metals, and combinations thereof.

31: The system of any of Aspects 20-30, wherein the oxygen transferagent comprises ii) and the reducible metal oxide comprises ametal-boron oxide; and

a magnesia-phosphate cement;

wherein:

the average oxidation state of the metal in the metal-boron oxide isfrom 2.7+ to less than 4.0+, and the oxygen transfer agent comprises 10%or less of a stoichiometric excess of Mn with respect to the boron; and

the magnesia-phosphate cement comprises: MgM′″PO₄.mH₂O, wherein m is aninteger from 0 to 6; and

wherein the metal-boron oxide comprises at least one compound thatsatisfies the formula M′₂M″BO₅,

wherein M′ is selected from one or more of alkaline earth metals,actinide metals, lanthanide metals, and combinations thereof; and M″ isselected from one or more of trivalent transition metals.

Aspect 32: The system of any of Aspects 20-31, wherein the oxygentransfer agent comprises iii) and the reducible chalcogen comprises:

(A) 10 to 90 wt % CaSO₄;

(B) 1 to 85 wt % of a total of W and at least one of Fe and/or Mn; and

(C) 1 to 10 wt % of an alkali metal salt.

Aspect 33: The system of any of Aspects 20-32, wherein the oxygentransfer agent comprises ii) and the reducible metal oxide furthercomprises at least one promotor comprising at least one of alkalinemetals, alkaline earth metals, boron, sulfur, salts of tungstic acid,salts of halides, or mixtures thereof.

Aspect 34: The system of any of Aspects 20-33, wherein the oxygentransfer agent comprises i) water and the reduced oxygen transfer agentcomprises H₂.

Aspect 35: A method of converting CO to CH₄ comprising:

a) contacting a first process stream comprising the CO and at least oneC1 to C12 saturated and unsaturated hydrocarbons with a hydrogenationcatalyst and a source of H₂; and

b) reacting at least a portion of the CO with the H₂, at reactionconditions, to provide a second process stream comprising the CH₄ andwater;

wherein the at least one of C1 to C12 unsaturated hydrocarbons are notreduced in step b); and

wherein the first process stream comprising the CO is a hydrocarbonproduct stream resulting from the oxidative coupling of methane oroxidative dehydrogenation of hydrocarbons.

Aspect 36: A system for converting CO to CH₄ comprising:

at least one reactor configured for:

a) contacting a first process stream comprising the CO and at least oneC1 to C12 saturated and unsaturated hydrocarbons with a hydrogenationcatalyst and a source of H₂; and

b) reacting at least a portion of the CO with the H₂, at reactionconditions, to provide a second process stream comprising the CH₄ andwater;

wherein the at least one of C1 to C12 unsaturated hydrocarbons are notreduced in step b); and

wherein the first process stream comprising the CO is a hydrocarbonproduct stream resulting from the oxidative coupling of methane oroxidative dehydrogenation of hydrocarbons.

EXAMPLES

The following non-limiting example is provided for the purpose ofelucidating the advantages obtained from aspects of the presentinvention and are not intended to limit the invention to only theseexemplary embodiments.

Example 1

Mass flow simulations were performed using ChemCAD version 7.1.6 12867to model the conversion of the CO to CO₂ in a typical ODH productionstream via a catalytic steam reforming reactor placed downstream of theODH reactor. The process modeled is shown in FIG. 3 and the results ofthe steam reforming and CO₂ removal are shown in Tables 2-8. The resultsshown used the built-in water gas shift model option in ChemCAD and alsoused a stoichiometric model for the OHD reaction in the ODH reactor,using experimentally determined conversions as indicated in the tables.

This system may convert from 1 to 100% of the CO per pass to CO₂ on amass basis and may result in the removal of at least 70%, or at least71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88,89, 90, 91, 92, 93, 94, 95, 96, 97, 98, or at least 99% or up to 100% ofall carbon oxide byproducts from the desired ODH olefin product mixture,on a mass basis, performing multiple passes if necessary.

TABLE 2 Compositions of Streams 10 and 20 in FIG. 3 Stream 10 Stream 20Ethane Feed Reactor Feed kg/hr wt % mol/hr mol % kg/hr wt % mol/hr mol %Hydrogen Methane 0 0.00% 0 0.00% 0 0.00% 0 Acetylene Ethylene Ethane142,435 100.00% 4737 100.00% 215,965 100.00% 7182 Propylene Propane 00.00% 0 0.00% 0 0.00% 0 Butadiene Butene Butane Pentane Benzene TolueneCO CO₂ Water Total 142,435 4737 215965 7182

TABLE 3 Compositions of Streams 30 and 35 in FIG. 3 Stream 30 Stream 35Reactor Product Water kg/hr wt % mol/hr mol % kg/hr wt % mol/hr mol %Hydrogen 3795 1.44% 1882 15.90% Methane 7605 2.89% 474 4.00% Acetylene935 0.36% 36 0.30% Ethylene 113,034 43.00% 4029 34.02% Ethane 73,64428.02% 2449 20.68% Propylene 2418 0.92% 57 0.49% Propane 211 0.08% 50.04% Butadiene 4079 1.55% 75 0.64% Butene 403 0.15% 7 0.06% Butane 4170.16% 7 0.06% Pentane 1244 0.47% 17 0.15% Benzene 935 0.36% 12 0.10%Toluene 189 0.07% 2 0.02% CO 7 0.00% 0 0.00% CO₂ 6310 2.40% 143 1.21%Water 47,643 18.12% 2645 22.33% 47,643 2645 Total 262,869 11,842 47,6432645

TABLE 4 Compositions of Streams 36 and 40 in FIG. 3 Stream 36 Stream 40COx Demethanizer Feed kg/hr wt % mol/hr mol % kg/hr wt % mol/hr mol %Hydrogen 3722 1.78% 1846 20.47% Methane 7605 3.64% 474 5.26% Acetylene 00.00% 0 0.00% Ethylene 114,041 54.59% 4065 45.08% Ethane 73,644 35.25%2449 27.16% Propylene 2418 1.16% 57 0.64% Propane 211 0.10% 5 0.05%Butadiene 4079 1.95% 75 0.84% Butene 403 0.19% 7 0.08% Butane 417 0.20%7 0.08% Pentane 1244 0.60% 17 0.19% Benzene 935 0.45% 12 0.13% Toluene189 0.09% 2 0.02% CO 7 0.12% 0 0.18% 0 0.00% 0 0.00% CO₂ 6310 99.88% 14399.82% 0 0.00% 0 0.00% Water 0 0.00% 0 0.00% Total 6318 144 208,9089018.1

TABLE 5 Compositions of Streams 45 and 46 in FIG. 3 Stream 45 Stream 46Hydrogen Fuel Gas kg/hr wt % mol/hr mol % kg/hr wt % mol/hr mol %Hydrogen 3350 53% 1662 90% 372 185 Methane 2962 47% 185 10% 4643 289Acetylene Ethylene Ethane Propylene Propane Butadiene Butene ButanePentane Benzene Toluene CO CO₂ Water Total 6312 1846 5015 474

TABLE 6 Compositions of Streams 50 and 55 in FIG. 3 Stream 50 Stream 55De-ethanizer Feed C3+ Stream kg/hr wt % mol/hr mol % kg/hr wt % mol/hrmol % Hydrogen Methane Acetylene Ethylene 114,041 58%  4065 61%  Ethane73,644 37%  2449 37%  Propylene 2418 1% 57 1% 2418 24%  57 31%  Propane211 0% 5 0% 211 2% 5 3% Butadiene 4079 2% 75 1% 4079 41%  75 41%  Butene403 0% 7 0% 403 4% 7 4% Butane 417 0% 7 0% 417 4% 7 4% Pentane 1244 1%17 0% 1244 13%  17 9% Benzene 935 0% 12 0% 935 9% 12 7% Toluene 189 0% 20% 189 2% 2 1% CO CO₂ Water Total 197,581 6698 9896 183

TABLE 7 Compositions of Streams 60 and 70 in FIG. 3 Stream 60 Stream 70C2 Splitter Feed Product Ethylene kg/hr wt % mol/hr mol % kg/hr wt %mol/hr mol % Hydrogen Methane Acetylene Ethylene 114,041 61% 4065 62%114,041 99.90% 4065 99.91% Ethane 73,644 39% 2449 38% 114 0.10% 4 0.09%Propylene Propane Butadiene Butene Butane Pentane Benzene Toluene CO CO2Water Total 187,685 6514 114,155 4069

TABLE 8 Composition of Stream 75 in FIG. 3 Stream 75 Recycle Ethanekg/hr wt % mol/hr mol % Hydrogen Methane Acetylene Ethylene Ethane73,530 2445 Propylene Propane Butadiene Butene Butane Pentane BenzeneToluene CO CO₂ Water Total 73,530 2445

Within this specification, embodiments have been described in a waywhich enables a clear and concise specification to be written, but it isintended and will be appreciated that embodiments may be variouslycombined or separated without departing from the invention. For example,it will be appreciated that all preferred features described herein areapplicable to all aspects of the invention described herein.

In some embodiments, the invention herein can be construed as excludingany element or process step that does not materially affect the basicand novel characteristics of the invention. Additionally, in someembodiments, the invention can be construed as excluding any element orprocess step not specified herein.

Although the invention is illustrated and described herein withreference to specific embodiments, the invention is not intended to belimited to the details shown. Rather, various modifications may be madein the details within the scope and range of equivalents of the claimsand without departing from the invention.

What is claimed is:
 1. A method of converting CO to CO₂ comprising, a)contacting a first process stream comprising the CO and at least one ofC1 to C12 saturated and unsaturated hydrocarbons with an oxygen transferagent; and b) oxidizing at least a portion of the CO to CO₂ and reducingat least a portion of the oxygen transfer agent to a reduced oxygentransfer agent, at reaction conditions, to provide a second processstream comprising the CO₂, the reduced oxygen transfer agent, and the atleast one of C1 to C12 saturated and unsaturated hydrocarbons; whereinthe C1 to C12 saturated and unsaturated hydrocarbons are not furtheroxidized; and wherein the oxygen transfer agent comprises at least oneof: i) water; ii) at least one reducible metal oxide; iii) at least onereducible chalcogen; mixtures of any combination of two or more of i),ii), and iii).
 2. The method of claim 1, further comprising, prior tostep a), performing a step at) comprising oxidative coupling of methaneor oxidative dehydrogenation of hydrocarbons at hydrocarbon oxidationreaction conditions to produce the first process stream.
 3. The methodof claim 2 wherein the oxygen transfer agent comprises i) water and thestep at) produces the water that is used as the oxygen transfer agent instep a).
 4. The method of claim 3, wherein step a1) and step a) areperformed in the same reactor.
 5. The method of claim 2, wherein theoxygen transfer agent comprises ii) or iii) and the same oxygen transferagent ii) or iii) is used in step at) and step a).
 6. The method ofclaim 5, wherein step a1) and step a) are performed in the same reactor.7. The method of claim 1, wherein the oxygen transfer agent comprisesii) and the at least one reducible metal oxide comprises at least one ofalkaline earth metals, actinide metals, lanthanide metals trivalenttransition metals, or combinations thereof.
 8. The method of claim 1,wherein the oxygen transfer agent comprises ii) and the at least onereducible metal oxide comprises at least one of Li/Mn/B/MgO,Li/Mn/B/CaSO₄/MgO, Na/Pr₆O₁₁, Mn, Fe, Mo, Ti, V, Pr, Cu, La, Ga, Tb, Nd,Dy, or mixtures or combinations thereof.
 9. The method of claim 1,wherein the oxygen transfer agent comprises ii) and the reducible metaloxide comprises at least one of M₃BO₅, a compound that satisfies theformula M′₂M″BO₅, or mixtures thereof; and wherein M is selected fromthe group consisting of, alkaline earth metals, actinide metals,lanthanide metals, trivalent transition metals, and combinationsthereof; M′ is selected from the group consisting of, alkaline earthmetals, actinide metals, lanthanide metals, and combinations thereof;and M″ is selected from group consisting of, trivalent transitionmetals, and combinations thereof.
 10. The method of claim 1, wherein theoxygen transfer agent comprises ii) and the reducible metal oxidecomprises a metal-boron oxide; and a magnesia-phosphate cement; wherein:the average oxidation state of the metal in the metal-boron oxide isfrom 2.7+ to less than 4.0+, and the oxygen transfer agent comprises 10%or less of a stoichiometric excess of Mn with respect to the boron; andthe magnesia-phosphate cement comprises: MgM′″PO₄.mH₂O, wherein m is aninteger from 0 to 6; and wherein the metal-boron oxide comprises atleast one compound that satisfies the formula M′₂M″BO₅, wherein M′ isselected from one or more of alkaline earth metals, actinide metals,lanthanide metals, and combinations thereof; and M″ is selected from oneor more of trivalent transition metals.
 11. The method of claim 1,wherein the oxygen transfer agent comprises iii) and the reduciblechalcogen comprises: (A) 10 to 90 wt % CaSO₄; (B) 1 to 85 wt % of atotal of W and at least one of Fe and/or Mn; and (C) 1 to 10 wt % of analkali metal salt.
 12. The method of claim 1, wherein the oxygentransfer agent comprises ii) and the reducible metal oxide furthercomprises at least one promotor comprising at least one of alkalinemetals, alkaline earth metals, boron, sulfur, salts of tungstic acid,salts of halides, or mixtures thereof.
 13. The method of claim 1,wherein the step a) takes place in the presence of less than 5 wt % ofO₂ with respect to the total amount of CO in the first process stream.14. The method of claim 1, wherein the oxygen transfer agent comprisesii) or iii) and the method further comprises a step c) contacting thereduced oxygen transfer agent with a third process stream comprisingmolecular oxygen to provide a regenerated oxygen transfer agent.
 15. Themethod of claim 14, wherein the method further comprises a step d)feeding the regenerated oxygen transfer agent to step a) as the oxygentransfer agent.
 16. The method of claim 3, wherein the oxygen transferagent comprises ii) or iii) and the method further comprises a step c)contacting the reduced oxygen transfer agent with a third process streamcomprising molecular oxygen to provide a regenerated oxygen transferagent.
 17. The method of claim 14, wherein the method further comprisesa step d) feeding the regenerated oxygen transfer agent to step a)and/or to step at) as the oxygen transfer agent.
 18. The method of claim1, wherein the method further comprises a step e) removing at least aportion of the CO₂ from the second process stream.
 19. The method ofclaim 1, wherein the oxygen transfer agent comprises i) water and thereduced oxygen transfer agent comprises H₂.
 20. A system for oxidativelyconverting CO to CO₂ comprising: at least one reactor configured for: a)contacting a first process stream comprising the CO and at least one ofC1 to C12 saturated and unsaturated hydrocarbons with an oxygen transferagent; and b) oxidizing at least a portion of the CO to CO₂, at reactionconditions, and reducing at least a portion of the oxygen transfer agentto provide a second process stream comprising the CO₂, the reducedoxygen transfer agent, and the at least one of C1 to C12 saturated andunsaturated hydrocarbons; wherein the at least one of C1 to C12saturated and unsaturated hydrocarbons are not further oxidized; andwherein the oxygen transfer agent comprises at least one of: i) water;ii) at least one reducible metal oxide; iii) at least one reduciblechalcogen; any combination of two or more of i), ii), and iii).
 21. Thesystem of claim 20, wherein the first process stream is produced by astep at) comprising oxidative coupling of methane or oxidativedehydrogenation of hydrocarbons at hydrocarbon oxidation reactionconditions.
 22. The system of claim 21, wherein the oxygen transferagent comprises i) water and the step at) produces water that is used asthe oxygen transfer agent in step a).
 23. The system of claim 22,wherein step at) and step a) are performed sequentially in the samereactor.
 24. The system of claim 21, wherein the oxygen transfer agentcomprises ii) or iii) and the step at) utilizes the same oxygen transferagent ii) or iii) as step a).
 25. The system of claim 24, wherein stepa1) and step a) are performed sequentially in the same reactor.
 26. Thesystem of claim 20, wherein the oxygen transfer agent comprises ii) oriii) and the at least one reactor comprises an inlet and an outlet, andwherein the system further comprises a regeneration unit incommunication with the inlet and the outlet, wherein the regenerationunit is constructed and arranged to: c) receive at least a portion ofthe reduced oxygen transfer agent from the outlet; d) contact the atleast a portion of the reduced oxygen transfer agent with a gascomprising molecular oxygen to produce a regenerated oxygen transferagent; and e) feed the regenerated oxygen transfer agent to the inlet.27. The system of claim 20, wherein the system further comprises apurification unit in communication with the at least one reactor,wherein the purification unit is constructed and arranged to remove atleast a portion of the CO₂ from the second process stream.
 28. Thesystem of claim 20, wherein the oxygen transfer agent comprises ii) andthe at least one reducible metal oxide comprises at least one ofalkaline earth metals, actinide metals, lanthanide metals trivalenttransition metals, or combinations thereof.
 29. The system of claim 20,wherein the oxygen transfer agent comprises ii) and the at least onereducible metal oxide comprises at least one of Li/Mn/B/MgO,Li/Mn/B/CaSO₄/MgO, Na/Pr₆O₁₁, Mn, Fe, Mo, Ti, V, Pr, Cu, La, Ga, Tb, Nd,Dy, or mixtures or combinations thereof.
 30. The system of claim 20,wherein the oxygen transfer agent comprises ii) and the reducible metaloxide comprises at least one of M₃BO₅, a compound that satisfies theformula M′₂M″BO₅, or mixtures thereof; and wherein M is selected fromthe group consisting of, alkaline earth metals, actinide metals,lanthanide metals, trivalent transition metals, and combinationsthereof; M′ is selected from the group consisting of, alkaline earthmetals, actinide metals, lanthanide metals, and combinations thereof;and M″ is selected from group consisting of, trivalent transitionmetals, and combinations thereof.
 31. The system of claim 20, whereinthe oxygen transfer agent comprises ii) and the reducible metal oxidecomprises a metal-boron oxide; and a magnesia-phosphate cement; wherein:the average oxidation state of the metal in the metal-boron oxide isfrom 2.7+ to less than 4.0+, and the oxygen transfer agent comprises 10%or less of a stoichiometric excess of Mn with respect to the boron; andthe magnesia-phosphate cement comprises: MgM′″PO₄.mH₂O, wherein m is aninteger from 0 to 6; and wherein the metal-boron oxide comprises atleast one compound that satisfies the formula M′₂M″BO₅, wherein M′ isselected from one or more of alkaline earth metals, actinide metals,lanthanide metals, and combinations thereof; and M″ is selected from oneor more of trivalent transition metals.
 32. The system of claim 20,wherein the oxygen transfer agent comprises iii) and the reduciblechalcogen comprises: (A) 10 to 90 wt % CaSO₄; (B) 1 to 85 wt % of atotal of W and at least one of Fe and/or Mn; and (C) 1 to 10 wt % of analkali metal salt.
 33. The system of claim 20, wherein the oxygentransfer agent comprises ii) and the reducible metal oxide furthercomprises at least one promotor comprising at least one of alkalinemetals, alkaline earth metals, boron, sulfur, salts of tungstic acid,salts of halides, or mixtures thereof.
 34. The system of claim 20,wherein the oxygen transfer agent comprises i) water and the reducedoxygen transfer agent comprises H₂.
 35. A method of converting CO to CH₄comprising: a) contacting a first process stream comprising the CO andat least one C1 to C12 saturated and unsaturated hydrocarbons with ahydrogenation catalyst and a source of H₂; and b) reacting at least aportion of the CO with the H₂, at reaction conditions, to provide asecond process stream comprising the CH₄ and water; wherein the at leastone of C1 to C12 unsaturated hydrocarbons are not reduced in step b);and wherein the first process stream comprising the CO is a hydrocarbonproduct stream resulting from the oxidative coupling of methane oroxidative dehydrogenation of hydrocarbons.
 36. A system for convertingCO to CH₄ comprising: at least one reactor configured for: a) contactinga first process stream comprising the CO and at least one C1 to C12saturated and unsaturated hydrocarbons with a hydrogenation catalyst anda source of H₂; and b) reacting at least a portion of the CO with theH₂, at reaction conditions, to provide a second process streamcomprising the CH₄ and water; wherein the at least one of C1 to C12unsaturated hydrocarbons are not reduced in step b); and wherein thefirst process stream comprising the CO is a hydrocarbon product streamresulting from the oxidative coupling of methane or oxidativedehydrogenation of hydrocarbons.